Focus problems

[llamedos]

I thought I had a problem with focusing my Sigma 150-600mm sports lens which can’t make up its mind on whether to back focus or front focus when fitted to a Canon 7d Mkii so decided enough was enough and purchased a Canon 500mm f4 L but this is doing the same, so I set up a focus chart to do a micro adjustment on it, placed it as far away as I could from the camera which is 15 mtrs at 45 degrees to camera, good light, level and facing directly at the lens at the same height, set camera on a sturdy tripod switched off the os set aperture to wide open with the lowest iso and took 6 test shots but these came back as follows first shot heavily back focused second the same third a not so much back focusing about half way fourth front focusing slightly fifth same sixth shot a little back focusing , after adjustment it got closer to the focus line but still inconsistent, so connected the lenses to my 5D mkiii which and done same test and adjustments with better results but still inconsistent and then my old faithful 50D which results were more stable but still not perfect, now the acid test, with my 5Dmkiii ever so slightly back focusing on four out of six shots I went out in the field switched on the os and took some shots hand held got back and checked the shots and they all front focused. Before I condemn my Canon gear to the local canal and take up golf is there anything I can do differently.

 

[Bristolian]

If the results are inconsistent then maybe clean the contacts on the body and the lens and see if that helps.

I have the Sigma 150-600 C model (used with a Nikon D750) and when I tested mine I found the amount of adjustment needed changed widely at different target distances even if the focal length stayed the same. For example, at 600mm focal length the adjustments needed was +9 @ 3m, +8 @ 6m, +1 @ 15m & -6 @ infinity. Unless you have access to Sigma dock you can never get a good adjustment setting in camera. The dock gives you 16 adjustment point (4 focal length x 4 target distances) by the way.

PS: My neighbour used to have a boat called llamedos - it took me ages to figure it out

 

[u8myufo]

I thought I had a problem with focusing my Sigma 150-600mm sports lens which can’t make up its mind on whether to back focus or front focus when fitted to a Canon 7d Mkii so decided enough was enough and purchased a Canon 500mm f4 L but this is doing the same, so I set up a focus chart to do a micro adjustment on it, placed it as far away as I could from the camera which is 15 mtrs at 45 degrees to camera, good light, level and facing directly at the lens at the same height, set camera on a sturdy tripod switched off the os set aperture to wide open with the lowest iso and took 6 test shots but these came back as follows first shot heavily back focused second the same third a not so much back focusing about half way fourth front focusing slightly fifth same sixth shot a little back focusing , after adjustment it got closer to the focus line but still inconsistent, so connected the lenses to my 5D mkiii which and done same test and adjustments with better results but still inconsistent and then my old faithful 50D which results were more stable but still not perfect, now the acid test, with my 5Dmkiii ever so slightly back focusing on four out of six shots I went out in the field switched on the os and took some shots hand held got back and checked the shots and they all front focused. Before I condemn my Canon gear to the local canal and take up golf is there anything I can do differently.

This is just a copy and paste Bob, I am only the messenger but it may have some connection with what you are experiencing hopefully someone on here might be able to come up with an answer for you.

I have heard of this issue with Sigma lenses on EOS DSLRs from Canon. It led to a comment I made just yesterday that annoyed a few of the Sigma fanboys here. I believe this was one of the lenses (100-400) that Sigma issued a notice on their website for. The other lens (150--600) has its own fair share of similar issues. The common problem of Front Focus and Back Focus was sometimes (but not always) resolvable with the optional Sigma Lens Dock... but it had no effect on Autofocus inconsistency. This is an issue that plagues many, many Sigma lenses and sometimes, the lens performs well initially but later begins to become unreliable. This affects Canon cameras in particular but also affects Nikon users. I have no figures for Sony users. Sigma once claimed that users were at fault for using "old cameras" with their new lenses. The M5 is hardly old and is even sold new today.

I have the Canon M5, and basically I've been finding that Sigma's telephoto lenses often front/back focus. I know that this isn't an issue relating to focus adjustments since the sensor itself does the auto focusing.

Complaints about the Sigma 150-600mm (C) lenses not working properly with Canon DSLR camera are all over the internet. Unfortunately, a lot of us never think to look up these comments before buying a product. There's more than a few mentions of this here on the DPreview forums as well. Many (but not all) of the complaints relate to APS-C DSLRs like the 7D II, 60D and the 50D. In some cases, a Firmware update fixed issues but then when users upgraded their cameras with newer bodies the problems set in again. Google the words "Sigma lenses autofocus problems 150-600mm" (without the quotation marks) to see over a million search results on these key words.

 

[Mike.P]

This is just a copy and paste Bob, I am only the messenger but it may have some connection with what you are experiencing hopefully someone on here might be able to come up with an answer for you.

I have heard of this issue with Sigma lenses on EOS DSLRs from Canon. It led to a comment I made just yesterday that annoyed a few of the Sigma fanboys here. I believe this was one of the lenses (100-400) that Sigma issued a notice on their website for. The other lens (150--600) has its own fair share of similar issues. The common problem of Front Focus and Back Focus was sometimes (but not always) resolvable with the optional Sigma Lens Dock... but it had no effect on Autofocus inconsistency. This is an issue that plagues many, many Sigma lenses and sometimes, the lens performs well initially but later begins to become unreliable. This affects Canon cameras in particular but also affects Nikon users. I have no figures for Sony users. Sigma once claimed that users were at fault for using "old cameras" with their new lenses. The M5 is hardly old and is even sold new today.


Complaints about the Sigma 150-600mm (C) lenses not working properly with Canon DSLR camera are all over the internet. Unfortunately, a lot of us never think to look up these comments before buying a product. There's more than a few mentions of this here on the DPreview forums as well. Many (but not all) of the complaints relate to APS-C DSLRs like the 7D II, 60D and the 50D. In some cases, a Firmware update fixed issues but then when users upgraded their cameras with newer bodies the problems set in again. Google the words "Sigma lenses autofocus problems 150-600mm" (without the quotation marks) to see over a million search results on these key words.

It also does it with his Canon 500mm L f/4 so it's not just the Sigma.

 

[billgatese30]

I had a similar problem with my Sigma 35mm Art. The in camera adjustment wasn't good enough and as @Bristolian said, the only way to nail it was with the sigma dock. Fortunately my 150-600 is pretty good on my 5diii but my 35mm was exactly as you described. Pick up a 2nd hand Sigma USB Dock and try adjusting it on that.

 

[Nod]

and take up golf is there anything I can do differently.

I'd advise against taking up golf! The frustration that those little balls cause as they fly off into the neighbouring fields, streams, long grassy areas etc. while avoiding the holes puts missed focus in the shade!!!

Hopefully an introduction to a Sigma dock will cure the problem for you.

 

[the black fox]

Yes it does seem to be a problem . To date my best results have come with matched maker lenses ,canon/canon Nikon/Nikon olympus/Olympus it’s a ongoing problem most likely down to movements within the AF systems over time . I sometimes regret the demise of the old split screen MF of old it was a pain but worked well .
Saying that I find MF on olympus to be pretty good but not perfect